Safety lock switch



2 Sheets-Sheet 1 Filed Oct. 31, 1966 INVENTORS fan 2, J/msozz,

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July 23, 1968 RlNK ETAL- 3,393,540

SAFETY LOCK SWITCH Filed Oct. 351, 1966 2 Sheets-Sheet 2 f INVENTORSC/aytozz RJ/E/mson, BY 6 680296 R122]:

United States Patent 3,393,540 SAFETY LOCK SWITCH George Rink, 219Endwell St., Walled Lake, Mich. 48088, and Clayton R. Johnson, 2328Briggs Drive, Drayton Plains, Mich. 48020 Filed Oct. 31, 1966, Ser. No.590,902 4 Claims. (Cl. 70-237) This invention relates to key operatedlocks in general and more particularly to key operated switches and thelike for use in electrical power supply systems.

Key operated switches are most commonly known as used in automotive andother vehicles in the electrical system which provide ignition sparkcontrol for the vehicle engine. The key operated ignition'switch enablesonly authorized persons to start and drive a vehicle and is therefore animportant security measure.

Unfortunately, ignition keys and like means in other electrical controlsystems are too often forgotten and left in the switching device whichthey safeguard. This is particularly true with automotive vehicles wheredistractions at the last moment in parking a car, carelessness and plainabsentmindedness cause the key to be left in the ignition switch afterthe engine is turned off.

It is an object of this invention to provide a device for use with keyoperated electrical switches and the like which requires that the key beremoved from the switch before the electrical circuit is broken.

It is an other object of this invention to provide means wherebystandard type key switches may 'be modified to incorporate therequirement of key removal without extensive and costly tooling changes.

Still another object of this invention is to provide a key operatedswitching device wherein normal accessory positions for operating otherelectrical equipment is available with or without the security featurementioned.

These and other objects will be more apparent in the discussion whichfollows of two like but different embodiments of the present inventionand which makes reference to the accompanying drawing.

In the drawings:

FIGURE 1 is a side elevation of an ignition type lock cylinder and keywith the safety device of this invention incorporated therewithin.

FIGURE 2 is 'a front end view of the key lock shown in the first drawingfigure.

FIGURE 3 is an enlarged cross section of the key lock modification ofthis invention as seen in the plane of line 3--3 of the first drawingfigure.

FIGURE 4 is a similar to the last mentioned drawing figure with certainparts shown in different operative positions.

FIGURE 5 is a cross-sectional view of the key lock modification of thethird drawing figure as seen in the plane of line 5-5 thereon.

FIGURE 6 is similar to the last mentioned drawing figure with the keypartly withdrawn and parts shown in different operating positions.

FIGURE 7 is a cross-sectional view of a like but different key lockmodification, without the key.

FIGURES 8 and 9 are similar to the last mentioned drawing figure withthe key in the lock and parts shown in different operative positions.

FIGURE 10 is a cross-sectional view of the key lock modification shownin the seventh drawing figure as seen in the plane of line 1010 thereon.

This invention may be incorporated within a standard key lock switchsuch as is used for the ignition switch on most automotive vehicles. Or,it may be provided as a sub-assembly part for use therewith.

In the drawings, the sub-assembly arrangement is shown in which anintermediate part 10 is provided be- 3,393,540 Patented July 23, 1968tween the lock cylinder 12 and the chrome ring part 14 normally providedon the vehicle instrument panel.

Within this small intermediate part is the working mech anism' of one ofthe embodiments of this invention which will now be described.

The lock cylinder 12 is of the conventional type which includes an outerhousing having a tumbler 16 in which is provided a key slot 18. Theproper key 20 for the lock permits the tumbler to be turned in onedirection or the other to make a suitable electrical connection (notshown) to the engine ignition system.

The intermediate part 10 is essenially a ring of sufficient width toreceive a slider 22 through a side wall for reciprocal movement relativeto the key slot 18. The slider includes a guide slot 24 in which isreceived a pin 26- to limit travel towards the key slot and spring 28 isprovided in the guide slot to bias the slider in that direction.

Immediately over the top end of the guide slot is provided a latchingmember 30. One end is pinned for pivotal movement, as at 32, and theother end is formed to include a latching pawl 34 for holding engagementwithin a notch 36 in the slider 22.

The latching member 30 is biased by spring means 38 for engagement withthe top edge of the slider 22 and for seating engagement in the notch36, when permitted. When it is disposed in holding engagement with theslider, the latching member crosses over the top end of the key slot 18.This is to provide for engagement by the key 20 when the key is removedfrom the key slot; as will later be discussed.

A small roller 40 may be provided on the lower edge of the latchingmembers 30 to guard against wear, where engaged by the key 20, ifdesired.

Mounted outside the lock cylinder, separate or thereon, and near the endof the slider 22 is a normally open switch, shown as a pair of contacts42. This switch may operate a warning light or be part of the electricalcircuit of the ignition system. In the first instance the warning lightwould be lit while the contacts are closed, or, if in the ignitioncircuit, electrical power would be provided to the ignition circuituntil the contacts are separated.

Considering now the embodiment of FIGURES 16:

When a key 20 is inserted in the key slot 18 of a lock tumbler 16, itpasses through the intermediate part 10 and under the latching member30. The latching member rests on the top edge of the slider 22 behindthe notch 36 and the slider is biased towards the key and key slot sothat the switch contacts 42 are open.

With the key 20 fully inserted within the lock cylinder, for itsintended purpose, the part of the shank near the head of the key issufiiciently narrow, or is made to include a depression, so that thelatching member 30 may be engaged in the notch 36 of the slider 22. Toposition the slider for this engagement, the key 20 is turned, as shownin FIGURE 4, to move the slider so that the latching pawl 34 falls intoplace. This also causes the slider to close the switch contacts 42 andto hold them closed.

Only when the key 20 is removed from the lock cylinder, so that one ofits higher teeth (and preferably the last one) trips the latching member30 is the slider released and the contacts 42 broken.

Accordingly, the key lock ignition switch shown is provided with asecondary switch which must be inactivated to either turn off a warninglight or finally cut the ignition to the engine.

Only the proper key can be turned in the ignition switch and only inturning the key is the safety switch set. Returning the key to theneutral or accessory position is not enough to break the secondarycircuit once it has been made. This is accomplished only when the key isremoved sufficiently from the key slot to trip the latching means 30that holds the slider 22 in contact making engagement with the secondaryswitch.

A second variation of this invention is shown in FIG- URES 7-10.

Where possible, like members indicate like parts from the previousdiscussion and those in the .100 series are similar but different.

The slider 122 is, in this instance, provided across the face of thetumbler 16 with an opening 124 through which the key slot is accessible.The side wall edges 123 and 125, about the opening 124, guide on lands126 formed and protruding from the end of the lock tumbler for suchpurpose.

The slider is disposed within the intermediate part behind a freelyrotatable cover shield 127 through which only a key slot is provided.The slider could be made to guide on this member if desired and therebyavoid any tooling revision as regards the tumbler.

A spring loaded detent 128 is provided within the outer wall of theintermediate part 10 and serves to bias the slider upwardly so that itslower edge covers part of the key slot access. When a key is inserted inthe key slot the slider is depressed and the detent serves to close theswitch contacts 142 much in the manner previously described.

In this second embodiment, the slider .122 includes a switch holding campart 136 on one side so that the switch contacts 142 stay closed as thekey and tumbler are turned and turn the slider with them.

As used in the ignition control circuit for a vehicle engine, thissecond safety switch would have its contacts 142 arranged to hold thecircuit once made but would not make the circuit when first closed.Otherwise, the key switch would be by-passed.

As will be appreciated, when the key is placed in the key slot 18 theslider 122 is depressed and it is held depressed until the key isremoved. Accordingly, in this second embodiment the key must becompletely removed to enable the contacts of the secondary switch toseparate.

If the cam part 136 is provided on only one side, as shown, the key maybe turned to the accessory position to break the secondary contact,Since the secondary switch contact should be in a holding circuit, itmay include an arcuate cam part on the other side as Well, with somerelief between the two to cut the ignition circuit but still operatesuch as a warning light.

From the foregoing two embodiments of this invention shown anddescribed, it will be appreciated that the safety lock feature isrelatively inexpensive to provide and practically fool-proof inoperation.

The switch operating device of the first group of drawing figures may beprovided by a simple modification at the neck of a standard lockcylinder, and the operating device of the last group of drawing figuresby a slight modification at the front end of the cylinder. Or, asmentioned, an intermediate part including all of the operating mechanismfor the secondary switching device may be provided for use with standardkey lock cylinders and the like.

In an ignition switch arrangement, there is an advantage to having thesecondary switch maintain the electrical connection to the ignitionsystem so that the key must be removed to turn off the vehicle engine.No one will leave a car running and if they must both turn off theprimary ignition switch and remove the key, there is an absoluteassurance that the key will not be left in the switching device.

The switching devices may also be provided in multiples for ignitionlocks or other uses, where desired. This is best seen with respect tothe second embodiment where two or more cam sliders could be stacked andhave the cam operating part provided on a side edge, or the top, foroperating other switching contacts. This may be used where a key can bereversed or where different switching functions, as for instrumentsafety signal lights, are to be operated separate from the switchactivated in turning the key.

Without further discussion it should be obvious that numerous othervariations, modifications and combinations are conceivable and withinthe scope of this invention.

Although two preferred embodiments have been specifically shown anddescribed in detail herein, it will be appreciated that this has beendone to illustrate the scope of the present invention and without intentto unnecessarily limit the invention thereto in any regard. Accordingly,such improvements, modifications and alterations as come to mind and arewithin the spirit of this invention and not specifically excluded by thelanguage of the hereinafter appended claims are to be considered asinclusive thereunder.

We claim:

1. A switch operating device, comprising;

a key lock cylinder having a key slot receptive of a key therewithin; aslider disposed near the front end of the lock cylinder and reciprocalnormal thereto,

an electrical switch disposed for actuation by said slider,

means for biasing said slider relative to said key slot and foractivation relative to said switch upon rotation of a key in said slot,

and latch means operable upon rotation of a key in said slot to holdsaid slider in actuating engagement with said switch and for the releasethereof upon removal of the key from said slot.

2. The switch operating device of claim 1,

said latch means having shoulder holding engagement with said slider.

3. The switch operating device of claim 2,

said latch means being disposed for holding engagement with said sliderbetween teeth of a key in said slot and for disengagement therefrom by akey tooth in the removal of the key from said slot.

4. The switch operating device of claim 3,

said latch means including a pivotal member extending transverselyacross said key slot and having a pawl disposed for engagement with saidslider,

said slider including a shoulder notch receptive of said pawl in holdingengagement therewithin,

and means biasing said pivotal member for engagement of said pawl insaid shoulder notch following lateral movement of said slider effectedby rotation of said key.

References Cited UNITED STATES PATENTS 2,519,940 8/1950 Smith et al.34052 2,536,918 1/1951 Dorfman 34052 2,623,133 12/1952 Evans 340522,786,194 3/1957 Hermenzie 34052 3,020,523 2/1962 McKeon 34052 3,138,7806/1964 Jacobson 34052 MARVIN A. CHAMPION, Primary Examiner.

R. L. WOLFE, Assistant Examiner.

1. A SWITCH OPERATING DEVICE, COMPRISING: A KEY LOCK CYLINDER HAVING AKEY SLOT RECEPTIVE OF A KEY THEREWITHIN; A SLIDER DISPOSED NEAR THEFRONT END OF THE LOCK CYLINDER AND RECIPROCAL NORMAL THERETO, ANELECTRICAL SWITCH DISPOSED FOR ACTUATION BY SAID SLIDER, MEANS FORBIASING SAID SLIDER RELATIVE TO SAID KEY SLOT AND FOR ACTIVATIONRELATIVE TO SAID SWITCH UPON ROTATION OF A KEY IN SAID SLOT,